<!DOCTYPE html>
<html>
<head>
    <meta charset="UTF-8" />
    <title>React 实例</title>
    <script src="https://cdn.staticfile.org/react/16.4.0/umd/react.development.js"></script>
    <script src="https://cdn.staticfile.org/react-dom/16.4.0/umd/react-dom.development.js"></script>
    <script src="https://cdn.staticfile.org/babel-standalone/6.26.0/babel.min.js"></script>
</head>
<body>
<div id="example"></div>

<script type="text/babel">
    class LoginControl extends React.Component {
        constructor(props) {
            super(props);
            this.handleLoginClick = this.handleLoginClick.bind(this);
            this.handleLogoutClick = this.handleLogoutClick.bind(this);
            this.state = {isLoggedIn: false};
        }

        handleLoginClick() {
            this.setState({isLoggedIn: true});
        }

        handleLogoutClick() {
            this.setState({isLoggedIn: false});
        }

        render() {
            const isLoggedIn = this.state.isLoggedIn;
            let button;

            if (isLoggedIn) {
                button = <LogoutButton onClick={this.handleLogoutClick} />;
            } else {
                button = <LoginButton onClick={this.handleLoginClick} />;
            }

            return (
                    <div>
                    <Greeting isLoggedIn={isLoggedIn} />
                    {button}
                    </div>
        );
        }
    }

    function UserGreeting(props) {
        return <h1>欢迎回来!</h1>;
    }

    function GuestGreeting(props) {
        return <h1>请先注册。</h1>;
    }

    function Greeting(props) {
        const isLoggedIn = props.isLoggedIn;
        if (isLoggedIn) {
            return <UserGreeting />;
        }
        return <GuestGreeting />;
    }

    function LoginButton(props) {
        return (
                <button onClick={props.onClick}>
        登陆
        </button>
    );
    }

    function LogoutButton(props) {
        return (
                <button onClick={props.onClick}>
        退出
        </button>
    );
    }

    ReactDOM.render(
    <LoginControl />,
            document.getElementById('example')
    );
</script>

</body>
</html>